Create a rule
To create a SYN flood rule or an out-of-state TCP rule:
- Log in to the Cloudflare dashboard and select your account. 
- Go to Account Home > L3/4 DDoS > Advanced TCP Protection. 
- Depending on the rule you are creating, do one of the following: - Under SYN Flood Protection, select Create SYN flood rule.
- Under Out-of-state TCP Protection, select Create out-of-state TCP rule.
 
- In Mode, select a mode for the rule. 
- Under Set scope, select a scope for the rule. If you choose to apply the rule to a subset of incoming packets, select a region or a data center. 
- Under Sensitivity, define the burst sensitivity and rate sensitivity of the rule (by default, Medium). The sensitivity levels are based on the initially configured thresholds for your specific case. 
- Select Deploy.